A 3rd generation partnership project (3GPP) based on a wideband code division multiple access (WCDMA) wireless access technique is being extensively developed all over the world. An high speed downlink packet access (HSDPA), which may be defined as a first evolution of the WCDMA, provides a wireless access technique with a competitive edge in the mid-term future to the 3GPP. However, as requirements and expectations of users and service providers are continuously increasing and development of competitive wireless access techniques is proceeding, a new technical evolution in the 3GPP is requested to ensure competitiveness in the future.
One of systems considered in the post-3rd generation is an orthogonal frequency division multiplexing (OFDM) system that can attenuate an inter-symbol interference effect with a low complexity. The OFDM converts serially inputted data symbols into the N parallel data symbols, includes them in the N separated subcarriers, and transmits the same. The subcarriers maintain orthogonality in a frequency domain. The respective orthogonal channels experience mutually independent frequency selective fading, and the intervals of transmitted symbols are lengthened to minimize the inter-symbol interference. Orthogonal frequency division multiple access (OFDMA) refers to a multi-access scheme accomplishing multiple accesses by independently providing portions of available subcarriers to each user in a system using the OFDM as a modulation scheme. The OFDMA provides frequency resources called subcarriers to each user, and in general, the respective frequency resources are independently provided to multiple users so as not to overlap with each other. That is, resultantly, frequency resources are mutually exclusively allocated to the users.
As the media broadcasts are digitalized, a digital broadcast service is supported through a wireless communication system. Following digital broadcastings such as a digital audio broadcasting (DAB) that allows transmitting characters, figures, video, or the like, as well as quality voice, a digital video broadcasting (DVB), a digital television broadcast standard of Europe, or the like, a digital multimedia broadcasting (DMB) service combining mobile communication and digital broadcast is in service, and research on a digital broadcast service in a wireless communication system is ongoing.
The digital broadcast service in a wireless communication system is provided such that a base station transmits the same contents to a plurality of user equipments. However, a reception performance of the contents varies due to a difference of channel environments according to a location or mobility of the user equipment. So, providing of the same contents without consideration of the channel environment or the reception performance of the user equipment is not effective in terms of quality of service (QoS).
Thus, a method for providing contents of various qualities according to a channel environment or a reception performance of a user equipment in a digital broadcast service through a wireless communication system is required.